1. BIOPOTENTIAL AMPLIFIERS

2. What is the need of bio amplifiers?
Bio signals have low amplitude and frequency.
So it is used to boost the amplitude level of the bio signals.
O/P is displayed in ECG or EEG

3. Types of Amplifiers Differential amplifier Operational amplifier
Instrumentation amplifier
Chopper amplifier
Isolation amplifier

5. Differential Amplifier
A differential amplifier produces an output voltage that is proportional to the difference between the voltage applied to the two input terminals.
The voltage gain for the differential signals is the same as for the inverting followers, provided the ratio equality of R2/R1 = R4/R3 is maintained.
Differential amplifiers are useful because it rejects common voltages while amplifying the differential signal of interest.

6. Operational Amplifier
Circuit Model of Operational Amplifier

7. Two types of Operational Amplifiers
1. Inverting Amplifier
2. Non-inverting Amplifier

8. Inverting Amplifier
Inverting amplifier consists of an op-amp, an input resistor (R1), and a feedback resistor (R2).
The noninverting input is grounded in this circuit.
The point A, the junction of the two resistors and the operational amplifier's inverting input, is properly called the summing junction, or summation node.

9. Derivation

10. Non-inverting Amplifier
In the non-inverting amplifier input voltage is applied directly to the non inverting input terminal of the operational amplifier .
Feedback resistor R2, and input resistor R1, are the same as in the inverting follower, except that the other end of R1, is grounded.

13. Who finishes first 
Write as many words from the letters in the box within 1 minute.